Sound-reproducer



E. J. RODGERS.

SOUND REPRODUCER.

APPLICATION FILED MAR. 21. 1919.

1,359,466, Patented Nov. 16, 1920.

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E. J. H ODGERS,

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E. J. RODGERS. SOUND REPRODUGERJ APPLICATION FILED MAR. 21. 1919.

Patented Nov. 16, 1920.

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ELWOOD J. RODGERS, OF OMAHA, NEBRASKA.

SOUND-REPRGDUCER.

Application filed March 21, 1919.

T 0 all to 720m it may concern:

Be it known that I, ELwooD J. Bone-Ens, a citizen of the United States, and a resident of Omaha, in the county of Douglas and State of Nebraska, have invented certain new and useful Improvements in Sound- 'Reproducers, of which the following is a specification.

My invention relates to sound reproducing mechanism, and especially to reproducers adapted for use with disk soundrecords having various types of recorngrooves therein. There are now extensively sold in this country three distinct types of disk sound records, of which the characteristics may be briefly stated as follows: (a) Records in which the spiral groove is lshaped in vertical section, and in which the undulations are lateral or in the plane of the disk. (6) Records in which the groove is U-shaped or rounded at the bottom and the undulations vertical or of the so-called hilland-dale form. (0) Records having vertical or hill-and-dale undulations, but in which the groove is essentially V-shaped in vertical section. To obtain satisfactoryreproduo tion from records of these various types, it is essential that the reproducer stylus should rest upon and traverse the record in as nearly as possible the same way as the recording stylus employed by the makers for cutting the original or master records. it is also necessary that the pressure of the stylus upon the record be suited to the type of record, and that the form of and materials used in the styli be suited to the respective records, if the most satisfactory reproduction is to be obtained. it is also desirable that the reproducing stylus should engage the record at the proper angle to the surface thereof, and that the stylus should be in a vertical plane substantially tangent to the record-groove at the point of contact of the stylus therewith, especially when the stylus-position is inclined to the surface of the record. lVith the foregoing in view, i is the object of my invention to provide a sound reproducer capable of use with records of any of the various types mentioned, and constructed so that it may be adjusted by a single simple operation to properly meet any of the various combinations of requirements above mentioned, according to the type of records to be reproduced; or, in other words, to provide a universal repro- Specification of Letters Patent.

Patented Nov. 16, 1920. Serial No. 284,226.

ducer with which, in changing from one type of record to another, a single simple ad usting operation serves to change all of the necessary structural factors for obtaining the most perfect results with each kind of record. A further object of my invention is to provide a metallic stylus-lever. oivoted in a plane offset from the plane of the diaphragm, but which may be directly con nected with the diaphragm without having a tendency to distort the same unsymmetrically and thus reduce the clarity of reproduction or the volume of sound. More particular objects of my invention will be hereinafter set forth in detail.

in the accompanying drawings Figure l is a side view of mechanism embodying my invention, the reproducer being adjusted for use with the first above mentioned (a) type of records, Fig. 2 is a horizontal section of the mechanism, mainly in the plane of the line 22 of Fig. 1, Figs. 3 and 4: are vertical sectional views taken respectively in the planes 3-43 and 4l-4 of Fig. 2, Fig. 5 is a partial side view, with the reproducer shown in vertical section and in position for use with records of the second above mentioned (Z5) type, Fig. 6 is a bottom face view of the r producer showing the diaphragm which is in operative position in Fig. 5, Fig. i' is a similar view showing the diaphragm used with the third above mentioned (a) type of records, 8 is a View similar to Fig. but having in operative position the diaphragm and stylus-lever shown in Fig. 7,

and Figs. 9 and 10 are dia rammatic views of stylus-levers and diaphragnis, illustrating the tendency of a rigid stylus-lever to distort the diaphragm unsymmetrically, and the way in which my improved stylus-lever avoids such unsymmetrical distortion.

The reproducer mcchanisr provided by my invention is intended for use in connection with any suitable machine for rotat ng a sound-record disk at a controlled uniform spec l, and having suitable sound-proje ing or amplifying means, such machines mg well known and usually having a horizontal rotary table A on which the rccord-(ilisk is laid and centered, and over which the reproducer is traversed, the latter being carried by a horizontally swinging tone-arm which connects the sound-box with the horn or anipli fyin sound-conduit. In the structure shown I employ a tubular tone-arm ll of the usual tapering term, the larger end thereof being turned downwardly and being pivot-ally connected with a fixed base 12 by any suitable means such that the horizontal portion of the arrn may swing ahove the rotary table It, parallel therewith, and to an extent such as to pass over the grooved portion of a record-dish upon the table. Near the outer or front end of the tone arm ll, the same is turned laterally to Form a hollow bearing-member tor a tubular arm 1+2 which is mounted thereon so as to be swingable in a vertical plane about said bearing member. A circular port if) in the front side of the bearingnleniber connects the passage through the tone-arm with that through the arm it. its shown in Fig. 52, said arm is held upon the heading by a washer l6 and screw 1? which passes through the washer into the closed end of the hollow hearingnieinber. Opposite the port 15 there is a slot 18 extending partially aronndthe wall of the member 1?. and a rod or small shalt lb, carried by the arm, tends through said slot to limit the suing- .1g movement of the arm about the bear member. Said rod 19 has an additional function. hereinafter set forth.

A thin collar 20 is formed integrally '-;vith the tubular arm 14- near its bearing on member 1a, and the sound-box sleeve tits revoluhly around said collar and the portion of the arm which extends beyond the At its outer or front end said sleeve elo bv a removable late 22, and adjacent to plate there is a transverse wall 23 integ'i with the sleeve and having an axial opening into which is fitted a portion of the rod or shaft 19, said portion of the shaft beii'ig squared, threaded terminally, and provide with a, nut 24, so as to he fixedly connee with the sleeve.

Diaphragm-oleings 30, it" and are termed integrally with the sleeve 21 and arranged in equilateral triangular 'iorni about the axis thereof as best shoivn in Fig. 3. Said casings are chambered c vlindrically receive respectively the diw phragnis 31,

ll and 51, the edges of the diaphragi'ns being he hetween pairs of re silient tubular r1 and (l n send perngherally cl:

the rhanib I therein by tal rings 35, are reniovaoly secured to t; casings by suitable screws. sides of the diaohr openings or p which is circular opens to the chamber, ially oi the sleeve- 21 an verselv as it approaches the that at the here each passa f tangnlar port ad d to 1: er with ports 25 and 26 iorni respectively at the a the tubular ar .1

tom and one side of In that P0512621 as shown clearly in Fig.

of the sleeve which fits around the collar 20 there is a radial opening in which is slidably fitted a shouldered pin 27 the head of said pin being slidable within a cap "28 screwed into a boss on the sleeve. as shown in Figs. 2 and e. Disposed within the 05-. p 28 is a spring :29 which presses the pin in toward the collar 20. pin is rounded and tits in a groove in tlze cellar said groove being of the circumferential extent shown in big. l, and lia -111g in ii e hottorn thereoi three depressions or seats 00, -15 and 55. adapted to receive the and of pin and to yieldi -gly retain the sleeve ill the respectively adjusted positions at which the pin is in re ister with said seats.

The rod or sl the slot 18 in the hearing-member 13, e tends through and lits revolubly within cylindrical boss 60 which is formed integrally with the huh-portion 0:? the arm 14., said boss extending hack from the huh in axial alinement with the tubular torwarzlly extending part of the arm. At its rear end the shaft 19 carries a eylindriral (itll'l-lQOdY 61 which has a helical groove 62 n the outer portion thereof. A. tubular'sh Gil lit-s slidably over the cam-body 1 and boss 60, the rounded rearward end oi said sleeve being lilled to form weight In the lower side of the sleeve 63, near the front end thereof, a longitudinal slot 65 is formed therein, and a small pin 66., carried on the boss 60, extends into said slot as shown in 8. so as to prevent rotation oil the sleeve but to permit tree longitudinal movement 1 relative to the boss. A pin 67, caron the inside of the sleeve. extends into the helical earn-groove 62, wherebv rotation of the shaft and cam-body causes longitudh nal movements oi? the sleeve. thus moving the counterweight formed by said sleeve and the weight 64, toward or frorn the axis oi the bearing-member 13 accoroing to the direction of rotation.

The several parts above described are so constructed and proportioned that when the sleeve 21 is in a position at which the pin 27 enters the seat 35, the diaphragm 31 is in a vertical position, or perpendicular to the face of the record-disk V on the table A, the sleeve 63 is at the extreme forward position shown in Figs. 1 and 2, and the passage 3 L is in register with the port 26 oi the tubular arm ll, while the openings to the passages at and 5 are opposite impertorate parts of said arm. This is the operative position for the diaphragm 31, which is alapted for use with sound-records of the type (a) first herein mentioned, wherein the undulations of the groove are lateral or in the plane of the disk. one end secured to the center of the diaphragm 31, and extends diagonally clownward and forward therefrom being pivoted The im er end of the A stylus-lever 36 has between lugs 37 on the ring 33, and the lower end of the lever having a socket for a removable stylus 38 which is retained therein by a set-screw 39. The stylus rests upon the face of the record in an inclined or angular position, and the pressure of the stylus against the record is proportional to that part of the weight oi the sound-box and the arm 14 which is not counterbalanced by the weight of the parts 60, 61, 63 and 64, it being understood that the several parts are so proportioned as to result in a proper stylus-pressure for records of the type mentioned above.

To adapt the mechanism for use with records of the second type (b) hereinbefore mentioned, it is merely necessary'to rotate the sleeve 21 about the tubular arm 14: from the position above described, in the direction oi": the arrows in Figs. 3 and 4:,

until the yieldable stop-pin 27 enters theseat 45 in the collar 20. At this position the diaphragm 4-1 is parallel with the face oi. the record P on the table A, the passage 4A is in register with the port 25 in the lower side of the tubular arm 14;, the passages 34 and 54 are opposite imperforate parts of the tubular arm, and the sleeve 63 with the counterweight 64 is moved slightly backward, as shown in Figs. 5 and 6, so that the effective counterweighting of the soundbOX is slightly greater than before. A stylus-lever 46, connected with the center of the diaphragm 4:1, is pivoted between lugs 17 on the ring 43, and has a downwardly and forwardly extending chuck or clamping socket 49 which retains removably a stylus 48. Said stylus has a rounded or ballshaped point adapted to enter the d-shaped grooves of the record P, and engages said record at an angular or inclined position, as indicated in Fig. 5.

By rotation of the sleeve 21 about the arm is until the stop-pin 27 enters the seat 55, the mechanism is adjusted for use with records of the third type (0) hereinbetore mentioned. At said position of the soundlOOX the diaphragm 51 is parallel with the face of the record E on the table A, the passage 54 is in register with the port 25 of the arm 14, the passages 34: and 4H: are opposite imperforate parts of the tubular arm, and the counterbalancing sleeve and weight 64: are at the extreme rearward position shown in Figs. 7 and 8. A stylus-lever 56, secured to the center of the diaphragm 51, is pivoted between lugs 57 on the ring 53, and at. its forward end has a vertical downwardly ex-. tending part 59 terminating in a relatively sharp or ll-shaped stylus-point 58, preferably formed by a diamond or other extremely hard material suitable for permanent use, set in the end of the vertical part 59. The stylus of this character requires less pressure upon the record than those of the two preceding types, and the reduced pres sure is obtained by having the auto1hatically variable counterweight 636 l at the extreme rearward position, where it has the greatest tendency to counterbalance the weight of the sound-box.

Special attention is directed to the fact that the styli 38, 4:8 and 58 are so arranged that when in operative position the points thereof will each be the same distance from the vertical pivotal axis of the tone-arm 11, so that, without change of length of the tone-arm, each stylus will traverse a record with the point moving along an arcuate line, such as the line r in Fig. 2, nearly radial to the record-disk, and such that the line if continued will pass through the center of the disk. Each stylus and styluslever is also arranged so that when in operative position it will lie in a vertical plane substantially tangent to the record-groove at the point of contact of the stylus therewith, and extending through the pivotal axis of the tone-arm. Thus, it will be seen from Fig. 2 that the stylus-lever 86 is offset laterally from the center of the arm 14 the same distance that said arm is offset laterally from the tone-arm 11; and from Figs. 6 and 7 it will be seen that the stylus-levers t6 and 56 are disposed angularly to the longitudinal axis or" the arm 14; on which the sound-box is mounted, so that when in 0perative position the direction of the vertical plane inwhich said levers and their styli lie is such as to pass through the vertical pivotal axis of the swinging tone-arm and be substantially tangent to the recordgrooves at the point of contact of the styli therewith. The described positions of the several styli when in operation are desirable in order that the same may track in the grooves oi the record in the same way as the recording styli used in the production of the original or master records of which the commercial sound-records are duplicates; and unless the styli are arranged in this manner the same will be inclined laterally from the vertical plane tangent to the record-grooves at the point of contact, and the styli will ride one side or the other of the grooves, resulting in imperfect reproduction of the recorded sounds, excessive and uneven wear of the records, and a tendency, particularly with the angularly disposed styli, for the reproducer to skid or swing across the records transversely oi" the grooves.

A further refinement of structure is to be noted in the form of the stylusdevers near the ends thereof which are connected with the diaphragms. Referring to 2, 5 and 8, it will be seen that the main portion of each stylus-lever extends substantially parallel with the diaphragm. from the pivotal axis of the lever to a point slightly be- &

yond the center or the diaphragm, then turifs in perpendicularly to the diaphragm, and finally at the face of the diaphragm turns baclr toward the pivotal axis of the lever, the return-bent end-portion being attached to the diaphragm. lhe advantage of this structure may be perceived by reference to 9 and 10, in connection with the following: Unless a very small diaphragm or an excessively long stylus-lever is used, it is not practicable to pivot the stylus-lever in the plane of the diaphragm, this being an arrangement which would be desirable as resulting in movements of the attached end of the lever exactly perpendicular to the diaphragm. ln avoiding excessive length of the stylus-lever with a large diaphragm (which it is desirable to use for the salre of tone-volume and fullness of the reproduced sounds), the pivot or fulcrum or the stylus-lever is oll'set from the plane ot the diaphragm; but, as a result or said offsetting of the lever tulcrum, the attached end oi? the lever tends to move angularly to the diaphragm, or in the direction oi the line tangent to the arc y struck from the leverdfulcrum e in Fig. 9. With a rigid stylus lever, the tendency of said angular movement is to distort the diaphragm unsymmetrically, the bowing thereot occurring at the side opposite the lever-tulcrum, as indicated by dotted lines in Fig. 9, and the other side or half of the diaphragm being but slightly bowed, or even assuming a curvature opposite in direction to that of the principal curvature or bowing first mentioned. ()bviously such unsymmetrical dis tortion of the diaphragm is undesirable and will result in imperfect sound-reproduction. With a lever extend'ng in a substantially straight line from the pivotal axis thereof to the diaphragm, as in Fig. 9, ii": the lever be made su'liicieutly flexible to compensate for the angular variation and thus permitthe attached end to move exactly per-pert dicularly to the diaphragm, there will be a marked loss of volume oi? the reproduced sounds, due to the cushioning or absorbing oil the vibration in the 'l'lQXll'llQ lever. lieferring now to Fig. l0, it will. be seen that the main portion of the styluslever may as sutliciently rigid to give full tone-volume in the reproduction, and that a slight lateral flexibility of the inwardly turned endportion of the lever will fully compensate for the tendency to move an. ularly at the taco otli'the diaphragm, enabling the attached end of the lever or fly perpendicularly to face, whereby produce a symmetrical distortion or bOWlPQ' oil the dis ahraom.

its the sound-vibrations are transmltted longitudinally of the inturned end-portion of the lever, it will be obvious that the necessary lateral flexibility thereof may be attained without reducing the capacity of the lever to transmit fully the vibrations received from the stylus, to thus produce the maximum tone-volume. The extent of the diaphragm-distortion indicated in Figs. 9 and 10, is, of course, greatly exaggerated in order to clearly illustrate the described tendencies of the different structures, and th resultant effects upon the quality of tone-reproduction.

.lteferring again to the adjusting operations oi the mechanism necessary in changing from one type of record to another, it will be noted that all necessary adjustment of the mechanism is effected by merely turning the multiple sound-box about the arm it so as to place the proper stylus in the operative or playing position therefor. The extent of the slot 18 in the bearing-member 13 is such as to permit lifting of the soundboX to a height sufficient to entirely clear the e of the table A or a record-dish thereon, -en rotating the sound-box to the desired position. It will be apparent that, by the s mplicity of adjustment, the use ct separ to styli and stylus-levers for each type i' record, and the perfect adaptation of each unit to its particular type, records of all the standard and commercially known styles me be used without special knowledge or sl-z l on the part of the user, and all values of the several types of record preserved as to as when the same are used in connection with machines for the single types only.

ow, having described my invention, what I claim and desire to secure by Letters Patent is:

Sound reproducing mechanism includa tubular arm mounted to swing vertiiv and horizontally; asound-box mounted ably upon a portion of said arm and ug a plurality of diaphragms and styli apted to be brought into operative position serially by rotating said sound-box to predetermined positions upon the arm; means for counterbalancing a portion of the weight of the sound-box and arm, and means actuated by rotation of the soundbox for automatically varying the ellective counterbalance according to the position of the sound-b0): upon the arm.

Elound reproducing mechanism includ ing a tubular arm mounted to swing about a fired axis, a sound-be): mounted rotatably upon a portion of said arm and having a plurality of diaphragm-chambers formed therein, there being ports in the tueular arm tempted to register with passages through sound-bo2r extending to the respective diaphragm-chambers, diaphragms mounted for vibration in said chambers, stylus-levers connected with said diaphragms and extenddiagonally to the longitudinal axis of the tubular arm, and styli carried by the several stylus-levers and movable into operative tor position solely by rotation of the sound-box 1 about the arm, the points of said styli when in operative position being substantially equidistant from the fixed axis of the tubular arm.

3. Sound reproducing mechanism including a horizontally swing-able tone-arm, a tubular arm connected with said tonearm and swingable vertically, a sound-box mounted rotatably upon said tubular-arm said sound-box having a plurality of diaphragm-chambers therein with passages extending therefrom and adapted to register with ports in the tubular arm, diaphragms mounted in said chambers, a stylus-lever for each diaphragm, said stylus levers being pivoted upon the sound-box and operatively connected with the respective diaphragms, the pivots of the several stylus-levers being in fixed and invariable radial relation to the axis of the tubular arm about which the sound-box is rotatable, and said stylus-levers being adapted for holding styli in operative record-engaging position when the soundbox is rotated to the positions at which the passages from the respective diaphragm chambers are in register with the ports in the tubular arm.

l. in a mechanism of the class described, a tone-arm pivoted upon a fixed vertical axis, a normally horizontal tubular arm jointed to said tone-arm and swingable vertically, a sound-box having a central bore and a plurality of diaphragm-chambers arranged symmetrically thereabout and having passages communicating with said bore, diaphragms mounted in said chambers, a stylus-lever and stylus for each diaphragm, the tubular arm fitting within the central bore of the sound-box so that the latter is rotatable thereon, said arm having a port adapted to register with the passage from one diaphragm-chamber when the respective diaphragm is vertical and the styluslever and stylus thereof in operative relation to a horiontal record-dish, said arm having a second port adapted to register with the passages from the other diaphragm-chambers when the respective diaphragms are horizontal and their stylus-levers and styli are in operative relation to a horizontal record-disk, the points of the several styli when in operative position being substantially equidistant from the pivotal axis of the tone-arm, the several styli and styluslevers when in operative position lying substantially in vertical planes intersecting the pivotal axis of the tone-arm, and the box for varying the effective counterbalance.

6, In a mechanism of the class described, a multiple sound-box having a plurality of diaphraglns and styli connected operatively with the respective diaphragms, a vertically swingable arm carrying said sound-box, the sound-box being rotatable about said arm and the several stylus-and-diaphragm units being moved into operative positions solely by rotation of the soundbox about the arm, a movable counterweight for the sound-box, and actuating means connecting the soundbox and said counterweight, whereby the latter is moved to a definite position for each position of the soundbox relative to the arm.

7. In a mechanism of the class described, .1 horizontally swingable tone-arm having a laterally turned hollow bearing-portion, a tubular arm mounted on said bearing-portion. and swingable thereabout in a vertical plane, a multiple sound-box having a p1urality of diaphragms and styli operatively connected with the respective diaphragms, said soundbox being mounted rotatably upon said tubular arm and movable about said arm to bring the several stylus-and-diaphragm uits successively into operative positions, a movable counterweight for the sound-box, and an actuating member for said counterweight, said actuating member being inclosed by the tubular arm and rotatable therein and connected fixedly with the scundbox whereby relative rotative movement of the sound-box and said arm may definitely vary the position of the counterweight.

E. J. RODGERS. 

